Saturday May 18, 2024

Fixed a Williams System 7!
  Posted by: AceBHound on Aug 21st, 2010 5:58 PM
The day isn't even over yet and I've already used the SA-20 Eprom Programmer to fix a Williams System 7 Pinball MPU board! Can't complain about that one bit! I had been battling with this Williams System 7 board for several days, battling with trying to get the programmer working before that. The System 7 board was acting really weird and as it turns out, 2 of the 4 EPROMs on the board matched ROM checksums with files from IPDB (Internet Pinball Database), one EPROM was bad, and the other EPROM had the wrong checksum. Programmed 2 new 2716 EPROMs to replace those, fired the board up on my test bench & no more weird error codes. What amazed me is the factory labels on these had IC17 and IC20 labeled wrong. I originally swapped them and it didn't help any, but when I finally peeled the labels back one was a 2532 (should be IC17 but was labeled IC20), the other was a 2716 (just the reverse of the labeling).

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